Full sight restored to blind mice using new stem cell therapy

Jan 9, 2013

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Full sight restored to blind mice using new stem cell therapy

Stem cell research is, what we could say, an important step in modern medicine. These cells hold the capacity of self-renewal and differentiation into any other type of cells. There are two types of stem cells, embryonic stem cells and adult stem cells. The embryo stem cells have the functions of dividing through mitosis, development and differentiation(Pluripotent cells).The function of “repairing system” of the body belongs to adult stem cells and progenitor cells.The foundation of stem cell research is based on discoveries made by by Ernest McCulloch and James Till at the University of Toronto in the 1960s’.

Researches have been conducted, in order to determine the possibility of restoring full sight of blind mice. The studies have been made on a batch of 12 mice which were suffering from lack of photoreceptors sensible to light. The method used was to insert cells in state of development into the eyes of the mice, and observe the progression within a period of time. The cells used were precursor cells extracted from mice. Signs of redevelopment of a new layer of cells sensitive to light have appeared within an estimated time of two weeks.

In order to determine the level up to which the cells improved eye – sight, another test led to the observation that there is a stronger response in pupil constriction in response to light stimulae. This observation helped the scientists to conclude that the increased amount of transplanted cells have allowed them to accomplish another specific function – that of regeneration of certain connections for visual improvement.

Several videos have shown that mice which could not differentiate between light and dark , are now prone to hide in dark places. Professor MacLaren states that there have been several successful trials conducted on patients in order to restore the pigmentation line of the retina. He adds that, due to this new discovery, he would like to make use of pluripotent stem cells or even iPS cells to reverse blindness in humans. These cells are taken from the cells belonging to the patient (also called autologous harvesting) and will be directed into also forming precursor cells of the retina, but the main dilema consists on the level of reliability of the source from which the cells are extracted.

The successful result of the researches have led to a possible future aid for patients suffering from Retinitis pigmentosa – a progressive blindness due to death of cells from the retina that are sensitive to light. However, the research continues, so the final result to be the achieved on patients – full eye sight restoration.

‘We have shown the transplanted cells survive, they become light-sensitive, and they connect and reform the wiring to the rest of the retina to restore vision,’ he says. ‘The ability to reconstruct the entire light sensitive layer of the retina using cell transplantation is the ultimate goal of the stem cell treatments for blindness we are all working towards.’ said Professor MacLaren.